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ZZZ <br /> a a I <br /> a o SERVICES, INCORPORATED <br /> a d — <br /> l� <br /> MPDS-UN2859--08 <br /> August 29 , 1995 <br /> Unocal Corporation <br /> 2000 Crow Canyon Place, Suite 400 <br /> P O Box 5155 <br /> San Ramon, California 94583 <br /> Attention Mr Robert A. Boust <br /> RE Quarterly Data Report <br /> Former Unocal Service Station #2859 <br /> 1665 Pacific Avenue <br /> Stockton, California _ <br /> Dear Mr Boust <br /> This data report presents the results of the most recent quarter of <br /> monitoring and sampling of the monitoring wells at the referenced site <br /> by MPDS Services, Inc <br /> RECENT FIELD ACTIVITIES <br /> The monitoring wells that were monitored and sampled during this <br /> quarter are indicated in Table 1 Prior to sampling, the wells were <br /> checked for depth to water and the presence of free product or sheen <br /> The monitoring data and the ground water elevations are summarized in <br /> Table 1 The ground water flow direction during the most recent <br /> quarter is shown on the attached Figure 1 <br /> Ground water samples were collected on August 10 , 1995 Prior to <br /> sampling, the wells were each purged of between 7 5 and 11 gallons of <br /> water During purging operations, the field parameters pH, tempera- <br /> ture, and electrical conductivity were recorded and are presented in <br /> Table 2 Once the field parameters were observed to stabilize, and <br /> where possible, a minimum of approximately four casing volumes had been <br /> removed from each well, samples were then collected using a clean <br /> Teflon bailer The samples were decanted into clean VOA vials and/or <br /> one-liter amber bottles, as appropriate, which were then sealed with <br /> Teflon-lined screw caps, labeled, and stored in a cooler, on ice, until <br /> delivery to a state-certified laboratory Field blank, Trip blank and <br /> Equipment blank samples (denoted as ES1, ES2 and ES3 respectively) were <br /> also collected for quality assurance and control . MPDS Services, Inc <br /> transported the purged ground water to the Unocal Refinery located in <br /> Rodeo, California, for treatment and discharge to San Pablo Bay under <br /> NPDES permit <br /> ANALYTICAL RESULTS <br /> The ground water samples were analyzed at Sequoia Analytical Laboratory <br /> • and were accompanied by properly executed Chain of Custody documenta- <br /> tion The analytical results of the ground water samples collected to <br /> 2401 Stanwell Drive Suite 300 Concord CA 94520 <br /> TEL (510)602 5120 FAX (510)689-1918 <br />